WILDERNESS MEDICINE
Wilderness Dermatology: Bugs, Plants, and Other Nuisances That May Ruin Your Hike
DOMINIC J. WU, MD; JENNIFER LEE, MD; AFTON CHAVEZ, MD; JOHN C. KAWAOKA, MD
16 22 EN ABSTRACT reaches higher in altitude, the total amount of UV radiation Spending time outdoors can be rewarding. However, ex- exposure increases as much as 30% for every 1000 meters.4 posure to the sun, insect bites, and plant exposures may result in a wide range of dermatologic manifestations. a. Sun Protection In this article, we describe potential cutaneous mani- All people older than 6 months of age, regardless of skin festations of common wilderness exposures in New En- color, should apply a broad-spectrum and water-resistant gland including photodermatoses from prolonged sun sunscreen of at least SPF 30. It is also important to re-apply exposure, phytodermatoses from plant exposures, and sunscreen at least every 2 hours, and after each water expo- arthropod-bite reactions from common insects (mosqui- sure. Patients should seek shade when possible, avoid sun tos, spiders, ticks, hymenoptera, mites and chiggers). The at peak hours between 10am–2pm, and wear sun protective article will also address preventive and treatment strate- clothing including broad-brimmed hats and sunglasses. The gies which may help physicians and their patients better American Academy of Pediatrics recommends that children prepare for spending time in the wilderness. younger than 6 months of age should have minimal expo- sure, wear appropriate clothing and have adequate shade. KEYWORDS: dermatology, wilderness, phototoxicity, arthropod reactions, plant exposure b. Drug-induced Phototoxicity Some medications can induce phototoxic rashes that resem- ble sunburns after sun exposure. Common offenders include NSAIDs, quinolones, tetracyclines, and diuretics. This side INTRODUCTION effect is thought to be due to UV light absorption by the Although hiking, biking, skiing, and other outdoor pursuits medication, leading to free radical formation and cellular are wonderful physical activities and can enhance one’s damage in sun-exposed areas. The severity of the effect is mental wellbeing, it is vital to take appropriate preventative often dose-dependent and linked to the duration and inten- measures to ensure the most enjoyable experience possible. sity of sun exposure. The phototoxic rash often occurs Environmental exposure to the sun and altitude puts one within 30 minutes of UV exposure and begins with burning at risk of sunburn and both acute and chronic skin damage. and pruritus, with or without wheals, and further develops Insect bites can induce an array of dermatologic manifes- into a bright red edematous photodistributed rash. This may tations that, if not appropriately managed, may result in progress to erythema, hyperpigmentation, edema, and even serious medical complications. Plant exposures can result blistering. in multiple cutaneous manifestations including allergic Management is supportive and involves prevention strate- contact dermatitis, phytophotodermatitis, irritant contact gies such as sun protection, limiting sun exposure, and dose dermatitis, and contact urticaria. reduction or elimination of the offending medication. Cool compresses and ice packs may offer significant relief. Simi- lar to sunburns, the patient should maintain hydration and SUN EXPOSURE use gentle emollients. Prolonged ultraviolet (UV) radiation exposure may result in cutaneous manifestations including sunburn, aging, and malignancies. Approximately 1 in 5 people in the United INSECTS States may develop skin cancer in their lifetimes.1 Both In the northeast United States, the most common cutane- UVA and UVB radiation may cause skin cancer, with UVA ous complaints from insect exposure are due to mosquitoes, primarily responsible for chronic skin changes such as pho- mites and chiggers, gypsy moths, fleas, spiders, hymenop- toaging, wrinkling, and lentigines.2 Even on cloudy days, up tera, and ticks. Their bites may contain toxins and irritants to 80% of harmful UV radiation can reach the skin.3 As one that can cause a wide range of dermatologic manifestations.
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a. Mosquitos c. Ticks Mosquitos are vectors for many diseases including West Nile Ticks can carry a multitude of diseases including Lyme dis- virus, encephalitis, and more. Mosquito bites classically ease (Table 1). Tick bites are typically not painful, as their present as pruritic wheals and papules, often with a central saliva contains anesthetic and anticoagulant factors. punctum. Depending on the victim’s immune response, Lyme disease typically presents with the erythema these bites may appear as urticaria, vesicles, or even as gran- migrans rash (red macule or thin plaque that slowly expands ulomatous lesions.5 outwards with central clearing resembling a target). The Prevention strategies include avoiding sites with stagnant incidence of Lyme disease has increased since 2007, and the water, wearing light-colored long-sleeved clothing to easily geographic distribution has broadened from primarily New identify mosquitos, utilizing mosquito nets, and wearing England, the Mid-Atlantic States, and Wisconsin to include insect repellant. Insect repellant containing DEET 10–35% adjacent states.11 If the tick is identifiable as I. scapularis, or picaridin 20% can be quite effective,6 and clothes can also has been attached to the host for more than 36 hours and be washed with permethrin. is engorged in a Lyme-endemic area, prophylactic treatment Mosquito bites are generally self-limited. Ice packs, topi- with a single dose of doxycycline 200 mg orally may be cal steroids, and over-the-counter topicals such as pramox- administered within 72 hours of tick removal (if no other ine 1% cream, menthol-containing products, and oral contraindications).12 antihistamines may help patients with more severe and Ticks should be removed carefully using a pair of forceps symptomatic reactions.7 First-generation antihistamines are or a tick-removal device by grasping the tick as close to the more sedating than second-generation agents, but tend to be skin as possible and removing the parasite with gentle, steady more effective for pruritus. traction perpendicular to the skin without twisting.6,13 Tick bites may be prevented by wearing clothing treated b. Spiders with permethrin. Applying DEET-containing insect repel- Most spider bites encountered in the U.S. are harmless and lants, tucking pants into socks, wearing long-sleeved cloth- may induce a brief localized skin reaction that spontaneously ing and pants, and performing daily tick checks can help to resolves. However, black widow (Latrodectus mactans) and reduce potential exposure. brown recluse (Loxosceles reclusa) spider bites may require more directed medical care (Table 2). d. Hymenoptera (Bees, Wasps) Female black widow spiders are more commonly found Stings from bees and wasps can be incredibly painful, and in the South up to Southern New England and in the West. may even provoke anaphylaxis. Their stings often produce Their bites transmit a venom containing α-latrotoxin, which immediate burning and pain at the site, followed by an leads to a large release of acetylcholine. The bite site typi- erythematous wheal. This usually resolves spontaneously cally appears as a painful pink edematous papule or plaque within a few hours. However, some individuals have a more with central fang marks with possible central clearing. The exaggerated response, such as swelling greater than 6 inches victim may then experience muscle spasms and cramps in diameter lasting up to 7 days. More severe local reactions within an hour in the chest or abdomen that may mimic in select individuals may be due to venom-specific IgE anti- a myocardial infarction. Treatment options include intrave- bodies in sensitized victims.5 nous benzodiazepines for muscle spasms and narcotic pain To remove a bee or wasp sting, the victim should ideally medications. Antivenom can be considered up to 48 hours use a straight, hard surface such as the edge of a credit card after a bite if severe pain persists after routine therapy.8 to nudge out and remove the stinger. One should avoid using Brown recluse spiders are rare in the Northeast. The bite fingers or tweezers to remove the stinger, as this may squeeze itself may be only slightly painful. However, soon after the additional venom into the stinging site. Some stings, such as bite, a tender erythematous halo rash may develop. In many that of the honeybee, have venom sacs and attached muscu- cases, this progresses to central necrosis, sometimes even lature that may continue to pump venom if the sac is not requiring a skin graft. It is thought that sphingomyelinase removed. Intradermal skin allergy testing can be performed D in the venom triggers platelet aggregation and activates with dilute quantities of venom to identify individuals at thromboxane B2 which leads to skin necrosis.6,9 Treatment high risk of anaphylaxis to venom. These individuals at risk options are controversial; however, most experts suggest for hymenopteran anaphylaxis have the option of undergo- that overly aggressive management, such as excising the bite ing venom immunotherapy which has been shown to be site to prevent necrosis, is harmful and not indicated. Most effective. They should always carry a preloaded epinephrine suggest proper wound care and minor debridement, with or device for emergency administration.5,14 (Table 3) without antihistamines or dapsone.10
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Table 1. Tick-borne Illnesses
Disease/Organism/ Vector image Cutaneous findings and Non-cutaneous findings/ Treatments Vector clinical photo Tests Disease: Non-cutaneous findings: Doxycycline (even in children <8) Rocky Mountain -Fever Spotted Fever -Myalgias May use chloramphenicol if pregnant -Nausea, vomiting -Headaches Organism: Rickettsiae Rickettsii Tests: -Serology with indirect Tick vectors: immunofluorescence assay Dermacentor (IFA) andersoni Rocky Mountain Spotted Fever -ELISA Dermacentor variablis1 rash1 -8 legged tick Dermacentor variabilis -Brown to reddish brown in Cutaneous findings: may not color develop until 2-5 days after -Females: grayish markings of systemic symptoms present upper body -Red, purple macules on wrists, -Males: markings on entire ankles, forearms that later back of males become hemorrhagic à trunk, hands, feet
Disease: Cutaneous findings Non-cutaneous findings: Doxycycline in adults and children > 8 Lyme Disease Early: erythema migrans A) Early localized disease yrs old: 14–21 days -flu like symptoms Amoxicillin in pregnant women, Organism: children < 8 yrs old: 14–21 days Borrelia Burgdorferi B) Early disseminated disease For severe disseminated disease -facial nerve palsy - Ceftriaxone IV Tick vectors: -joint pain Ixodes scapularis -carditis Prophylaxis if 1) Tick is Ixodes scapularis tick and Ixodes pacificus C) Chronic disease has been attached for approximately 36 hrs Ixodes scapularis1 -persistent neurologic and Ixodes ricinus rheumatologic symptoms 2) Post exposure prophylaxis within 72 hours of tick removal -Black legged tick 3) Local rate of infection with Borrelia -Females: orange to red body Tests: 1 at least 20% surrounding the black scutum Erythema migrans -Enzyme immunoassay for IgM 4) Doxycycline isnot contraindicated -Males: body completely dark and IgG antibodies brown Late or chronic: Acrodermatitis When these criteria are met, chronica atrophicans (loss of -Western blot of enzyme treat with: subcutaneous fat with thin immunoassay positive or Doxycycline 200mg in single dose w/I atrophic skin in chronic disease equivocal 72 hours of tick bite for adults Doxycyline 4mg/kg in children > 8 yrs old (max dose 200mg) w/I 72 hrs of tick bite
Disease: See Lyme disease In severe infection, can have Non-cutaneous findings: Treatment: Babesiosis petechiae and ecchmyoses -flu like symptoms Atovaquone and Azithromycin for -fatigue 7-10 days Organism: malaise Babesia microti -fevers -chills For severe disease treat with Tick vector: -myalgias clindamycin IV and quinine Ixodes scapularis -occasionally mild hepatomegaly or splenomegaly
-Dark-colored urine due to hemolytic anemia
Tests: -CBC to look for hemolytic anemia -Reticulocyte count
-Definitive diagnosis by Giemsa or Wright stains of blood smears which show ring forms and tetrads
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Table 1. Tick-borne Illnesses (continued)
Disease/Organism/ Vector image Cutaneous findings and Non-cutaneous findings/ Treatments Vector clinical photo Tests Disease: See Lyme disease Usually no exanthem, so Non-cutaneous findings: Doxycycline in adults and children > Anaplasmosis presence of cutaneous findings -Fevers 8 yo should raise suspicion for other -Malaise Organism: diseases or coinfection -Myalgias Anaplasma Headaches phagocytophilium -Nausea, vomiting -Confusion Tick vector Ixodes scapularis Tests: -serology by IFA Ixodes pacificus -ELISA -PCR Disease: Exanthem present in 10% of Non-cutaneous findings: Doxycycline in adults and children > Ehrlichiosis cases -Fevers 8 yo -Faint, blanching generalized -Malaise Organism: erythema -Myalgias Ehrlichia chaffeenis -Erythematous macules, Headaches papules, petechiae -Nausea, vomiting Tick vector: -Confusion Amyblomma -Meningoencephalitis americannum -Cranial nerve palsies
1 Female lone star tick Tests: Females: characterstic dorsal -serology by IFA white spot -ELISA Male: scattered spots/streaks -PCR around perimeter of body e. Mites and Chiggers rash. Wild parsnip (Pastinaca sativa) is found throughout Mites are small arthropods with eight legs whose bites may New England and may cause a severe phytophotodermatitis cause pruritic papules. Its six-legged larval form is called reaction. the chigger, which appear as tiny red insects that crawl Cutaneous manifestations include burning and painful, around until they reach a barrier such as lining of a sock. bullous, erythematous eruptions, which may result in The mites’ saliva sometimes provokes an allergic reaction chronic skin hyperpigmentation.15 Treatment is mostly from the human host, producing a pruritic papule. Mite and symptomatic (with cool compresses and oral antihistamines chigger bites classically present as grouped 1–2 mm pruritic if needed), and prevention involves avoidance of triggers. red papules with an abrupt demarcation line around borders With appropriate sun protection and time, the post-inflam- of clothing such as around the ankles. matory hyperpigmentation should resolve spontaneously. These bites tend to be self-limited and may be treated symptomatically for more severe reactions. Prevention and b. Irritant contact dermatitis treatment strategies are similar to those for mosquitos. There are two main categories of irritant contact dermati- tis (ICD) from plant exposures: mechanical (physical injury), and chemical. PHYTODERMATOSES Mechanical ICD is a result of physical trauma to the skin Exposure to plants may result in a variety of cutaneous man- caused by a plant’s trichomes (hairs), spines, glochids (barbed ifestations including phytophotodermatitis, irritant contact hairs), or thorns. These defense mechanisms may breach the dermatitis, allergic contact dermatitis, and contact urticaria. epidermis and trigger a papular eruption. A classic exam- ple of this are cacti which contain spines and sometimes a. Phytophotodermatitis glochids, which, if a person is exposed, may present as ery- Phytophotodermatitis is a cutaneous eruption resulting from thematous papules and nodules that spontaneously resolve the exposure of skin to photosensitizing agents from plants with time. such as furocoumarins (eg. psoralen) which react with UV Chemical ICD is often provoked by plant chemicals such radiation. Some plants that are known to cause phototox- as calcium oxalate that may be transferred to the epidermis icity include lemon, lime, celery, carrots, dill, and anise. A after physical contact with a plant, resulting in subsequent common presentation is a patient who squeezed limes out- inflammation. Daffodils commonly cause erythema, dry doors and subsequently developed a burning, erythematous skin, as well as scaling of the finger tips among florists due
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Table 2. Arthropod and Snake Reactions
Organism and image Presentation Treatment Organism and image Presentation Treatment Scorpion 2 -Pain and -Remove Gypsy moth -Eczematous, -Strip bite site paresthesias of stinger pruritic dermatitis with adhesive bite site -Supportive -Urticaria tape to remove -May have care caterpillar hairs neurological or -Ice -Wash site with cardiopulmonary -Antihistamines soap and water complications -Topical or oral steroids for severe reactions Bees, wasps, hornets -Ranges from Remove stinger, Io moth 4 -Immediate Same as gypsy pain and local symptomatic pruritus and moth edema at site of care stinging of bite to urticaria, involved skin respiratory distress, anaphylaxis Fire ants 2 -Line or ring of Symptomatic pustules with care surrounding red or Puss caterpillar 4 -Intense burning Same as gypsy hemorrhagic halo pain moth -May have -Hemorrhagic neurologic linear track marks systemic symptoms, anaphylaxis Snake bite -Fast onset Emergency: -Crotalidae: rattlesnake, pain, swelling, visit closest copperhead 3, and cottonmouth hemorrhage, emergency moccasin necrosis department. Saddle back caterpillar 4 -Immediate Same as gypsy Antivenom, painful stinging moth tentanus -Redness prophylaxis, -Edema possible antibiotics
Black widow spider 5 -Acute edema -Antivenom -Elapidae: coral snake (touching -hourglass-shaped marking on -Pain -Benzodiaz- red and yellow bands) 3 abdomen -Symptoms epines resembling a -IV calcium surgical abdomen gluconate
References 1. Images from: Tickborne Diseases of the United States. Center for Disease Control and Preven- tion. Fourth Edition. 2017. Brown recluse spider 5 -Erythema -Ice 2. Images from: Insects and Scorpions. Center for Disease Control and Prevention and National Institute for Occupational Safety and Health. Updated May 2018. https://www.cdc.gov/niosh/ -violin-shaped marking on head -Bullae -Elevation topics/insects/fireants.html -Necrosis -Possibly 3. Images from: Venomous Snakes. Center for Disease Control and Prevention and National In- -Possible dapsone stitute for Occupational Safety and Health. Updated May 2018. https://www.cdc.gov/niosh/ topics/snakes/default.html disseminated 4. Images from: Moths. Center for Disease Control and Prevention and Public Health Image Library intravascular (PHIL) https://phil.cdc.gov/AdvancedSearchResults.aspx?Search=Moths&parentid=15149&- catid=17125 coagulation 5. Images from: Venomous spiders. Center for Disease Control and Prevention and National In- stitute for Occupational Safety and Health. Updated June 2018. https://www.cdc.gov/niosh/ topics/spiders/types.html 6. Bolognia J and Schaffer JV. (2018). Dermatology. [Philadelphia]. Elsevier Saunders. 7. Jain S. (2012). Dermatology. [New York]. Springer.
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Table 3. Wilderness Dermatology Kit
While enjoying the wilderness, it is important to protect your skin and to have the necessary tools to decrease morbidity should a dermatological issue arise during your outdoors adventure. The authors of this article suggest stocking your dermatology wilderness pack with the following items for prevention and treatment. Over-the-counter Prescription-Only These items may require prescriptions from your doctor. Consider these items based on discussions with your doctor. Prevention • Broad brimmed hat • UV protective long-sleeved clothing • Broad-Spectrum sunscreen with an SPF of 30 or more • Sunglasses • DEET-containing insect repellant • Permethrin-treated clothing Treatment • Hydrocortisone 1% cream or ointment • Clobetasol 0.05% ointment (Ointments) • Vaseline • Hydrocortisone 2.5% ointment • Neosporin or other antibiotic ointment • Mupirocin antibiotic ointment • Anti-itch creams such as Sarna Treatment • Antihistamines (eg. Zyrtec, Benadryl, Claritin, Allegra) • Prednisone 10 mg tablets (Oral medications) • Doxycycline 100 mg tablets Dressings • Bandaids • Gauze • Medical Tape • ACE bandage • Tegaderm dressing to contact with calcium oxalate crystals. Reactions tend to CONCLUSION be self-limited and require no medical treatment. Hiking and spending time outdoors is a healthy and poten- tially therapeutic pastime. Exposures to insects, plants, and c. Allergic contact dermatitis the weather, however, can result in a multitude of symptom- Allergic contact dermatitis (ACD) is a type of delayed or type atic dermatologic manifestations. Equipping oneself with IV hypersensitivity reaction. Urushiol found in poison ivy, the knowledge of potential exposures and prevention and poison oak, and poison sumac, is a common cause of ACD in treatment strategies can help physicians prepare patients to the United States. Although poison ivy may appear as clus- make the most out of their time in the wilderness. ters of three leaves, poison oak and sumac have anywhere from three to 13 leaves. Clinically, these lesions appear as References erythematous pruritic patches and plaques within 48 hours 1. Sunscreen FAQs. Amer Acad Dermatol.
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10. Diaz JH, Leblanc KE. Common spider bites. Am Fam Physician. Authors 2007;75(6):869-873. Dominic J. Wu, MD, Cambridge Health Alliance Department 11. Shapiro ED, Wormser GP. Lyme Disease in 2018: What is new (and what is not). JAMA. August 2018; Epub 2 August, 2018. of Family Medicine 12. Nadelman RB, Nowakowski J, Fish D, et al. Prophylaxis with Jennifer Lee, MD, Brown University Department of single-dose doxycycline for the prevention of Lyme disease after Dermatology Ixodes scapularis tick bite. N Engl J Med. 2001 Jul 12;345(2):79- 84. Afton Chavez, MD, Brown University Department of 13. Flicek BF. Rickettsial and other tick-borne infections. Crit Care Dermatology Nurs Clin North Am. 2007;19(1):27-38. John C. Kawaoka, MD, Brown University Department of 14. Valentine MD, Schuberth KC, Kagey-Sobotka A, et al. The value of immunotherapy with venom in children with allergy to in- Dermatology sect stings. N England J Med. 1991;323:1601-1603. 15. Patel F, Zahir A, Ehrlich A. Plant-associated dermatitis. Derma- Correspondence tologist. 2012:20. John C. Kawaoka, MD Brown University Department of Dermatology 593 Eddy St, APC 1018, Providence, Rhode Island 02903 401-444-7139 [email protected]
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